A police officer is on patrol when he gets a call about a domestic dispute. When he arrives at the scene, he finds that an armed man has taken his girlfriend hostage and barricaded himself inside his apartment. The officer calls for backup, but when the other officers arrive, they realize that their standard guns won't shoot through the barricades. They don't have surveillance equipment to see inside the apartment, which would give them crucial information about the assailant and the hostage. If the assailant starts shooting at them, they don't have body armor to protect them from his bullets. They could use gas to incapacitate him, but they don't have access to it. They haven't been trained to storm the apartment and incapacitate the attacker with minimal risk of injury to the hostage, the officers and the assailant.

Luckily, most police forces have a special unit with the equipment and training needed to resolve exactly this kind of situation: the SWAT team. A SWAT (Special Weapons and Tactics) team is an elite unit within a police force, used for exceptional situations that require increased firepower or specialized tactics. The officers in a SWAT unit have undergone special training and have access to an arsenal of weaponry, armor and surveillance devices beyond standard-issue police gear. Much of this gear comes in the form of military surplus.

Here are a few situations that typically require a SWAT team call-out:

A high-risk warrant - If the police are going to conduct an arrest at a home, and they know the person is likely to be armed, they will call in the SWAT team to perform the arrest.

A hostage situation - SWAT team snipers are trained to take out an attacker who is holding a hostage in the event that negotiations break down.

A barricade situation - When criminals barricade themselves inside a building, possibly with weapons that are fired out at the police or civilians, a SWAT team can launch a powerful assault to end the stand-off.

A high-risk person - If someone needs to be transported, and there is a high chance of an assassination attempt on his life, SWAT team armored vehicles can serve as protection.

An armed terrorist attack.

A riot.

The Los Angeles Police Department is generally credited with developing the concept of SWAT in the 1960s. Political and social turmoil in the United States during that decade led police to decide that they were unequipped to deal with certain violent situations. The Watts Riots in 1965 and the 1966 sniper attack at the University of Texas in Austin reinforced the fact that they needed special equipment and procedures. Daryl Gates, a high-ranking LAPD officer who eventually became police chief, is often mistakenly credited with coming up with the idea of adopting military weapons and tactics for police units. However, Gates did use his position within the force to promote the idea of a SWAT team.

Initially, the SWAT unit was viewed with great skepticism by police officials, politicians and even other officers. The original acronym, "Special Weapons Attack Team," was viewed as too antagonistic, so Gates changed it to "Special Weapons and Tactics." Two incidents cemented the SWAT team's place within the modern police force: a barricade stand-off with members of the radical militant Black Panther Party in 1969, and a similar situation with the Symbionese Liberation Army in 1974. The next year, a network television series called "S.W.A.T." further embedded the idea of a SWAT team into American consciousness. Police units using paramilitary tactics quickly spread across the country, first through major cities with violent gangs, then filtering down to smaller cities.

Today, about 90 percent of all police forces in U.S. cities with a population of 50,000 or more have some kind of SWAT unit, while 70 percent of smaller municipalities have them. That equates to roughly 1,200 SWAT teams in the United States [Source: National Drug Strategy Network].

Next, we'll look at how police forces recruit and train SWAT team members.

Recruitment and Training

Members of a U.S. Army SWAT team engage targets as they enter a room during two-man team entry drills.

Police forces handle SWAT recruitment in different ways. In most cases, experienced officers volunteer for the job. If they meet the rigorous requirements, they are allowed onto the team. It's sort of like getting into a prestigious college. The desire to be on an elite squad drives these officers to take on the added responsibilities and duties. Other forces treat SWAT duty like another stage in an officer's career. In these departments, every cop eventually goes through two years of SWAT detail, whether they want to or not.

Training for SWAT team members can be grueling. No SWAT unit ever really "finishes" training -- they must maintain constant fitness and the ability to respond to situations automatically. Part-time SWAT units in smaller cities might train only 16 hours per month, while larger, full-time units spend far more time on training.

The regimen begins with physical fitness. Long distance runs, sometimes while wearing heavy body armor, are combined with push-ups, sit-ups, weight training and obstacle course training for agility. Marksmanship is another vital aspect of SWAT training. Most SWAT units require all members to be master marksmen, and many team members are qualified marksmanship trainers. Hitting a stationary target on a range isn't enough. Team members practice firing while on the move, selecting hostile targets from friendly targets, firing into barricaded rooms or vehicles and shooting with a greater degree of accuracy than the average cop. This training includes handguns, long guns and sub-machine guns. Some SWAT units travel to Gunsite, a world-renowned firearms training facility in Arizona.

SWAT teams rely heavily on practice scenarios and simulations. Although they can't replicate exactly what it's like to burst into a booby-trapped drug dealer's apartment or face down a gunman with a hostage, these trial runs are far more effective than simply talking about the situations. Depending on resources, teams may use computerized simulations or full-size mock-ups. Abandoned houses or wooden mazes populated with paper targets, mannequins or even other team members give SWAT agents a chance to try out various scenarios, learn from their mistakes and try again.

Certain members of the team may undergo more specialized training. Advanced training is available for snipers, explosives experts, surveillance experts and hostage negotiators. While most police departments prefer to keep negotiators and SWAT teams separate, the LAPD SWAT team puts every member through negotiator training, and most of the team members are qualified to take on the lead negotiator role. Additional training opportunities are offered by the FBI and some military branches.

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U.S. Army SWAT Team members review their actions after a training session.

The municipal costs of SWAT teams can vary tremendously. In a large urban area, the SWAT team is usually a dedicated, 24/7 unit with as many as 60 officers. Costs for equipment, training and personnel can run to seven figures. Smaller cities can get by with a 10-person team that carries out regular police functions, but can respond as a SWAT team when the need arises. This can cost somewhere around $100,000 per year or more, a significant amount for a small town. Start-up costs can be even greater.

Many municipalities have had success combining their resources with other counties and towns in the region to form a regional SWAT team. Each municipality has a few trained SWAT members and key pieces of equipment, allowing them to form a complete SWAT team when called on. Federal grants, many available through the Department of Homeland Security, can help police agencies pay for SWAT training and equipment.

We'll examine some of the gear used by SWAT team members in the next section.

Basic SWAT Team Gear

The SIG Sauer P220, a popular handgun choice among SWAT team officers.

Advanced weapons and equipment are part of what sets a SWAT team apart from regular patrol officers. SWAT officers piece together their body armor from military surplus and items purchased with federal grant money. Sometimes they buy their own.

Wearing body armor is a balancing act between protection, heat and freedom of movement. The torso and head are usually protected using Kevlar panels and a Kevlar helmet. Some SWAT body armor incorporates ceramic armor. For more information about the different types of body armor, check out How Body Armor Works.

Each SWAT officer has a lot of freedom in deciding which weapons he feels most comfortable using. The typical SWAT officer's arsenal includes a reliable, powerful handgun, a sub-machine gun and a shotgun. Officers trained for counter-sniper work will have a long-range rifle. Popular handgun choices include the Sig Sauer P220 and P226, 9mm guns made by Glock, Beretta or Heckler & Koch (particularly guns from the USP series). Many SWAT agents prefer the higher firepower provided by a Colt .45. Handguns are typically worn lower down on the leg than the hip holster common to patrol officers, with a modified holster for fast draws.

Semi-automatic weapons used by SWAT teams are often guns that were confiscated from drug dealers, so there's a lot of variety. Uzis, AK-47s and M-16s are all common, and the H&K MP-5 is another popular choice. All of these weapons can be equipped with silencing devices, allowing officers to take down suspects and maintain stealth if other hostile suspects are nearby.

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A hand-thrown M84 grenade delivers a loud bang and bright flash that can temporarily disorient people during a SWAT team raid.

There are several models of 12-gauge shotgun useful for SWAT purposes. The benefits of a shotgun include extreme stopping power at close range and the ability to hit a target quickly without having to take careful aim. Shotguns can also open doors, and shots bounced off of pavement can flush suspects from hiding places. Models by Remington, Benelli and Mossberg can be found in SWAT units throughout the United States. It is also possible to mount a shotgun under the barrel of a sub-machine gun. The Knight Master Key S and Ciena Ultimate are combination guns of this type.

SWAT teams make frequent use of flash-bang grenades and grenade launchers to incapacitate or scare off rioters. Foam, wood, rubber and bean bag rounds hurt suspects with a reduced chance of doing serious damage, while tear gas and pepper spray can leave someone gasping for air and in serious pain until the effects wear off. For photos and detailed information on these types of weapons, check out How Riot Control Works.

Police snipers are known to prefer bolt-action rifles. Many use hunting rifles modified for police use, while some pay to import European rifles. Laser and optical sights can be used. One restriction: military .50 caliber rifles have limited police use. They are so powerful that a shot can easily go straight through a suspect (or even a wall) and hit a hostage or bystander.

Most SWAT vehicles are scavenged and modified. Repurposed delivery vans, buses or armored cars can be found painted black. Extra armor may be added if the vehicle might be used for tactical purposes, such as driving the team into a dangerous area to begin an assault. Other SWAT vehicles are meant to stay behind the lines, acting as mobile command posts. Large motor homes are popular, though expensive. They have the advantage of providing a working bathroom for the team members to use during lengthy standoffs.

To gather intelligence on a situation, SWAT teams will use many forms of surveillance equipment. High-power binoculars are a basic necessity, and night vision goggles or scopes offer obvious benefits. Thermal imaging and even radar systems allow police to see the locations of people in total darkness, through dense smoke or fog, and sometimes through walls. A variety of tiny cameras and microphones can be used to surreptitiously gather more information about the actions and condition of suspects and hostages.

There's more to being a SWAT team member than weapons and other gear -- tactics play a huge part. We'll look at these next.

Tactics and Planning

Members of a U.S. Marine Corps military police SWAT Team assemble in riot control gear.

Ideally, SWAT officers don't see themselves as paramilitary soldiers, but as peace officers. This might seem to conflict with their aggressive and often violent tactics, but the optimal outcome of any SWAT team call-out is one in which no one is needlessly killed or injured. That includes hostages, innocent bystanders, officers and even the criminals themselves. SWAT tactics are meant to intimidate and confuse -- using deadly force is a last resort.

A typical SWAT call-out starts with the on-duty team members out on patrol, training or doing other police work. They may hear of an incident over their police radio that sounds like it could require SWAT. At this point, they have been given no formal command to assemble as a team, but they may begin preparing their gear and heading to police headquarters if they aren't in the middle of something that can't wait. The procedure for officially activating the SWAT team varies from one department to another, but generally a high-ranking police official will make the call. If more team members are needed, off-duty SWAT agents will be paged.

It may take an hour or more for the team to assemble. During this time, regular patrol officers will have secured the perimeter of the scene and kept it under surveillance. Once the SWAT team arrives at police headquarters, they will be briefed on the situation before loading into their SWAT vehicle. This vehicle transports the team and their gear, and in many cases it is also equipped to serve as a mobile command headquarters. Whether they use a vehicle or a nearby house or office, the team sets up their command post close to the scene of the incident, but in a safe place.

At the command post, team leaders begin assimilating information. Background checks on the suspect, the layout of the area, known weapons involved, the number and disposition of hostages, potential motives -- any information could be useful. At this point, negotiators get in contact with the suspect (if possible) and try to get additional information. (For more information on hostage negotiations, read How Hostage Negotiations Work). If the SWAT team is missing some crucial information, such as the specific location of the suspect and hostages in a barricaded house, they will send team members to gather it using surveillance equipment. These recon units usually operate as two-person teams, and they are experts at stealth.

One thing SWAT teams have learned over the years is that crazed gunmen don't always wait around for SWAT to execute a carefully-conceived plan. The suspect could start shooting at officers, killing hostages or make an escape attempt. For this reason, SWAT teams develop a few "quick and dirty" contingency plans as soon as they arrive on the scene.

Given enough time, the team will formulate a more extensive plan based on all the intel they have gathered. They will determine if there will be separate teams, where they will enter, the timing of the entry, what ordinance will be used and other details. There may be preliminary steps, such as drilling a small hole in a wall and using a pinhole camera to keep an eye on the suspect, or using a distraction to draw the suspect toward a certain location. If the SWAT team is going to serve a high-risk arrest warrant, they can spend more time planning.

In the next section, we'll examine how a SWAT team typically conducts a raid.

Active Shooters

Incidents like the Columbine High School shooting taught police that sometimes there isn't time to formulate any plan at all. The old doctrine of control, contain and negotiate could cost people their lives in a so-called "active shooter" incident. Now, SWAT teams and patrol officers alike know that sometimes they have to act immediately. An example of this new active shooter doctrine at work occurred in December 2006, when an angry man armed with a gun entered a Chicago office building and began shooting. While holding a hostage at gunpoint, the man was shot by a Chicago SWAT officer.

Conducting a Raid

When the SWAT team initiates a raid, it forms a single-file line known as the snake. This minimizes the number of team members who present an open target to armed suspects, though it obviously maximizes the risk to the officer at the front of the line. This officer is known as the point man. It's his job to enter an unknown room first (after other team members have forced the door open, if necessary) and neutralize any suspects that he encounters. The point man is the officer who most often has to make split second decisions. Is the person rushing at him armed? Is that a suspect holding a gun? Is that a hostage or a suspect? Such decisions are literally matters of life and death.

If you've ever watched a fictional SWAT team in action in a movie or TV show, you may have noticed how each team member enters a room and quickly drops into a certain position or covers a certain part of the room. That isn't fictional, and it doesn't happen by accident. Each team member has an Area of Responsibility (AOR). The instant they make entry into a room, each SWAT agent immediately covers his or her AOR. This is planned so that the officers aren't in each other's way, and ensures that the entire room is covered as quickly as possible. However, just like the defense of a football team reacting to different offensive plays, the officers react and adjust their AOR in response to events going on inside the room.

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Members of the Arlington Police Department SWAT team trail through a room in Quantico's Combat Town-2.

As the SWAT team enters the room or building, they will yell loudly, or they might use a "flash-bang," a grenade that creates more light and noise than actual concussive force. The aim is to disorient the suspects for at least a few seconds -- usually enough time for SWAT to have them covered with their weapons and face down on the floor.

An enormous number of variables can affect the outcome of a SWAT raid. The best case scenario is one in which the suspects surrender or are disoriented long enough to be pinned and cuffed by officers. Roughly 90 percent of all SWAT call-outs end without the SWAT team firing a single shot. Of course, raids can go bad. If the suspect forces a confrontation, he may be killed by the SWAT officers. Officers themselves can be shot, and hostages can be taken out by angry suspects or errant police bullets. That's exactly what SWAT teams train to avoid.

Regardless of the outcome, once the situation is resolved, the SWAT unit's work isn't done. First, there's paperwork to fill out. More importantly, every SWAT call-out is subject to a review and evaluation. The team discusses positives and negatives, and it uses that information to direct its training and correct problems in future call-outs.

We'll look at some of the criticisms of SWAT teams in the next section.

Criticism of SWAT Teams

Although most people agree that units of specially trained and armed officers are needed for high-risk situations, there is growing concern that SWAT teams are misused and overaggressive. SWAT teams are called out to serve warrants on non-violent offenders, or conduct raids based on information from criminal informants, leading them to raid the wrong house. They burst into people's homes unannounced, terrifying the residents, who often react in self-defense. There are several cases in which a SWAT raid has resulted in needless terror, property damage and death:

In a South Carolina high school drug raid, armed SWAT officers forced students as young as 14 to kneel or lie down at gunpoint while drug dogs searched bags and lockers. No drugs were found [Source: CNN].

In Maryland, a SWAT team entered a home in the middle of the night to serve a warrant on a teenager who had a small amount of marijuana. The teen's mother thought that criminals were entering the home and was holding a gun when SWAT officers entered. They shot her to death [Source: The Examiner].

A 75-year-old retired minister died of a heart attack when a Boston SWAT team raided the wrong apartment, chased and handcuffed him [Source: New York Times].

An optometrist was shot and killed by a SWAT officer when the team was called out to arrest him for betting on football games [Source: Washington Post].

The tactics used by SWAT teams invariably lead to charges of excessive use of force or wrongful death lawsuits. While many of these suits are settled for undisclosed amounts, they can range from tens of thousands of dollars to multi-million dollar settlements. The South Carolina high school SWAT, for example, cost the police department, town and school district $1.6 million.

For lots more information SWAT teams and related topics, check out the links in the next section.